This pace calculator solves any of the three running variables — pace, time, or distance — as long as you know the other two. Use it to find your pace per mile and per kilometer after a run, work out the finish time a goal pace produces, or figure out how far you covered in a set amount of time.
Results always show pace in both min/mile and min/km plus speed in mph and km/h, so you never need to convert by hand. A projection table extends your pace to the four classic race distances — 5K, 10K, half marathon, and marathon — to give an instant sense of what your current fitness translates to on race day.
The Pace, Time, and Distance Relationship
Everything in running math comes from one relationship:
Pace = Time ÷ Distance
Rearranged: Time = Pace × Distance, and Distance = Time ÷ Pace. Pick the variable you want and supply the other two.
Common race distances used in the projection table:
- 5K = 5 km = 3.107 miles
- 10K = 10 km = 6.214 miles
- Half marathon = 21.0975 km = 13.109 miles
- Marathon = 42.195 km = 26.219 miles
To convert pace between units, remember 1 mile = 1.609 km: a 8:00/mile pace equals about 4:58/km, and a 5:00/km pace equals about 8:03/mile. The calculator handles these conversions automatically and displays both.
Common Paces and What They Mean
Reference points to place your pace in context:
- 12:00/mile (7:27/km) — brisk walk / easy jog; ~2:37 half marathon
- 10:00/mile (6:13/km) — typical recreational runner; ~31:04 5K
- 9:00/mile (5:36/km) — around the median marathon pace; ~3:56 marathon
- 8:00/mile (4:58/km) — solid club runner; ~24:51 5K
- 7:00/mile (4:21/km) — competitive amateur; ~1:31 half marathon
- 6:00/mile (3:44/km) — sub-19 5K, sub-2:38 marathon territory
For training, most coaches prescribe easy runs 60–90 seconds per mile slower than race pace, with only 15–20% of weekly mileage at hard effort. Racing longer distances costs pace: a realistic marathon pace is typically 30–40 seconds per mile slower than your half-marathon pace.
Example: 25-Minute 5K
Say you ran a 5K in 25:00 and want your pace.
Pace per km = 25:00 ÷ 5 = 5:00/km. Pace per mile = 25:00 ÷ 3.107 = 8:03/mile. Speed = 5 km ÷ (25/60 hr) = 12.0 km/h, or 7.46 mph.
Held perfectly, that pace projects to a 50:00 10K, a 1:45:29 half marathon, and a 3:30:58 marathon. In practice, pace decays over distance — a common rule of thumb (Riegel’s formula) predicts closer to 51:56 for the 10K and 3:52 for the marathon — so treat flat-pace projections as a best-case ceiling and train specifically for the longer distance.
Frequently Asked Questions
How do I calculate my running pace?
Divide your total time by your distance. A 30-minute run covering 3.5 miles is 30 ÷ 3.5 = 8.57 minutes per mile, which converts to 8:34/mile (0.57 × 60 ≈ 34 seconds). Select "Solve for pace" above and the calculator does the decimal-to-seconds conversion for you.
What is a good running pace for beginners?
Most beginners run between 10:00 and 13:00 per mile (6:13–8:05 per km). The right easy pace is one where you can hold a conversation — for many new runners that includes walk breaks. Speed comes from consistent weekly mileage, not from forcing faster paces early on.
What pace do I need for a 4-hour marathon?
A 4-hour marathon requires averaging 9:09 per mile (5:41 per km) for 26.22 miles. Runners usually target a few seconds faster — around 9:05/mile — to bank a small buffer for water stops and late-race slowdown. For a 3:30 marathon, the required pace is 8:00/mile.
How do I convert min/km to min/mile?
Multiply the pace by 1.609 since a mile is 1.609 km. A 5:30/km pace is 5.5 × 1.609 = 8.85 minutes, or 8:51 per mile. Going the other way, divide: an 8:00/mile pace is 8 ÷ 1.609 = 4.97, about 4:58 per km.
Can I use my 5K pace to predict my marathon time?
Not directly — nobody holds 5K pace for a marathon. Flat-pace projections like the table above show a best-case ceiling; realistic predictors such as Riegel’s formula add roughly 6% slowdown each time the distance doubles. A 25:00 5K typically predicts a 3:50–4:00 marathon with proper endurance training.